The present invention is directed to a novel laminar tape structure in which a cloth scrim is sandwiched between an outer backing element and an adhesive layer. Since it is particularly useful in the preparation of so-called duct tapes, it will be described hereinafter by reference thereto.
As is well known in the art, duct tapes are customarily employed for such purposes as seaming metal ductworks, securing insulation and the like.
While in its simplest form, an adhesive tape may consist of a layer of adhesive coated onto a backing sheet in what may be called a two-layer structure, duct tapes should be strong as well as flexible. Consequently, an intermediate cloth layer or scrim is sandwiched between the adhesive layer and backing for increased strength in typical commercially available duct tapes.
In such commercially available duct tapes, the adhesive layer will in general be any of the per se known pressure-sensitive adhesives, e.g. an acrylic or rubber-based pressure-sensitive adhesive, and the backing will comprise a polyolefin, e.g. polyethylene.
Duct tapes of this description are entirely satisfactory for their intended usage and accordingly have achieved wide market acceptance. Nevertheless, it will be appreciated that, like any commercially available product, there is always a great need for cost effective manufacturing whereby the cost for producing a tape of comparable end use properties may be significantly reduced.
The aforementioned parent application, Ser. No. 923,939 is directed to the task of providing such a cost effective tape. In considering how to solve this task, the individual components or elements which constitute the product were considered and it was concluded that little or no cost savings could be realized by substitution of materials for the adhesive and cloth scrim. Consequently, attention was focused on the polyolefin backing which was typically on the order of about 5 mils thick and, in terms of raw materials, constituted a significant portion of the total cost.
In accordance with the invention described and claimed in the parent application, the task is solved in an elegant manner by substituting for the conventional backing material a foam tape backing provided with a thin outer skin. The novel tapes of the parent application therefore comprise a laminar structure consisting essentially of, in order, a thin skin outer layer; a layer of foam; a cloth scrim; and a layer of adhesive, e.g. a per se known pressure-sensitive adhesive.